As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L ENG BLEED WILL NOT CLOSE. REPLACED LEFT ENGINE PRSOV WITH ENGINE HIGH STAGE VALVE. NO HELP. REPLACED HIGH STAGE VALVE WITH PRSOV VALVE. SUSPECT LEFT ENGINE PRSOV REGULATOR. LEFT ENG PRSOV REGULATOR REMOVED. REPLACED PRSOV REGULATOR. ACCOMPLISHED IDLE RUN, CHECKS GOOD.